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>> It's not as good as a pure user-mode solution using tsc could be, but >> we've seen the kinds of complexities that has with multi-CPU systems, and >> they are so painful that I suspect the sysenter approach is a lot more >> palatable even if it doesn't allow for the absolute best theoretical >> numbers. > > The complexity only applies to nonsynchronized TSCs though, I would > assume. I believe x86-64 uses a vsyscall using the TSC when it can > provide synchronized TSCs, and if it can't it puts a normal system call > inside the vsyscall in question. You can't use the TSC to do gettimeofday on boxes where they aren't syncronised anyway though. That's nothing to do with vsyscalls, you just need a different time source (eg the legacy stuff or HPET/cyclone). M. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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